Classed by Sir Ranulph Fiennes as "the toughest journey on the planet", the expedition is highly ambitious and is expected to take 110 days through winter 2011-12 in the arctic and summer in the Antarctic.

"All my life I've wanted to walk in the footsteps of the great explorers" explained Mark. "But thanks to man's destruction of the planet, the paths they mapped no longer exist. The effects of climate change have left a very different landscape," says Mark.

Mark is using his challenge to engage people with the effects of climate change. He has set up an educational schools programme, where students can track his progress and speak to him at key milestones on his journey.
Using website The DoNation Mark is asking for support through action not cash, with donations ranging from eating less meat to installing solar panels. The total carbon by all will be added together to reach Mark's target of 100,000kg less carbon dioxide.

The DoNation is also now available for anyone else similarly inspired to take on their own snow-based challenge (perhaps on a less ambitious scale than Mark!) and raise sponsorship through The DoNation for it to help fight climate change.